A human body can be divided into the head, the upper limbs, the lower limbs, and the torso. Moreover, the front of the torso is divided into the chest region and the abdominal region. The chest region is constituted of the rib cage (a basket-like bone skeleton consisting of the breastbone, rib bones, and thoracic vertebra), the skeletal muscle group including the pectoral major muscle, the breasts, and the like. The rib cage is moved mainly in the vertical direction by breathing movement, and the skeletal muscles of the chest region, such as the pectoral major muscle, are also moved mainly in the vertical direction by daily movement of the upper limbs. Although the breasts cannot move by themselves, the breasts are positioned at an upper layer of the chest region, and thus can be moved under the influence of the vertical movement of the rib cage and the skeletal muscles of the rib cage, and under the influence of the gravity. Specifically, in the torso, the breasts move most significantly under the influence of breathing movement, daily movement of the upper limbs, and gravity. Moreover, a change in chest circumference accompanied by breathing movement is caused by a movement of the breastbone, rib bones and thoracic vertebra, which are the bones constituting the rib cage. Particularly, regarding movements of the breastbone and thoracic vertebra, the vertical movement of the breastbone is larger than the vertical movement of the thoracic vertebra due to the structures thereof. Specifically, a change in chest circumference accompanied by the breathing movement mainly occurs at the front of the rib cage, instead of the back of the rib cage. In other words, a change in chest circumference accompanied by breathing movement and the like does not occur evenly at the entire rib cage, but occurs most significantly at the precordial region that covers a forwardly facing base part of a garment with breast cups, such as a brassiere with breasts.
However, a conventional garment such as a brassiere that has a breast cups is configured such that a forwardly facing base part of a precordial region is constituted of a non-elastic material (a material having a small or substantially no elastic function), and a rearwardly facing base part of a back region is constituted of an elastic material (a material having a large elastic function). This means that the non-elastic and elastic functions of the forwardly and rearwardly facing base parts of the conventional garment such as a brassiere that has breast cups are not suitable for causing the breast cups to agree with the movement of the breasts moving under the influence of a physical change in chest circumference accompanied by breathing movement, by a movement of the skeletal muscles of the chest region accompanied by daily movement of the upper limbs, and by gravity. For this reason, the conventional garment such as a brassiere that has breast cups has a problem that the breast cups cannot agree with the movement of the breasts accompanied by breathing movement, by daily movement of the upper limbs, by gravity and the like.